But the lure to grow is there in part, officials say, because of the ambiguity of California's medical marijuana laws, which cast enough grey area to empower crooked growers who use the law to try to mask criminal activities.

On top of that, the federal government still considers marijuana illegal in all cases.

Marijuana will continue to be considered a highly dangerous drug under federal law with no accepted medical uses, after a U.S. appeals court Tuesday refused to order a change in the government's 40-year-old drug classification schedule.

The decision keeps in place an odd legal split over marijuana, a drug deemed to be as dangerous as heroin and worse than methamphetamine by federal authorities, but one that has been legalized for medical use by voters or legislators in 21 states and for recreational use in two.

Over the past few years, large-scale grows have made up 80 percent of the drug raids prosecuted by the San Joaquin County District Attorney's Office. The county and much of the Valley is considered a prime region for its vast farmlands and economic rental market.

"Now it's the majority of our caseload," Turner said. "They think they can get away with this stuff because of the vagueness of the laws."

State law allows patients and their primary caregivers to possess and farm marijuana for personal medical use, and it allows them to form cooperatives.

The problem is the law is "just too open-ended," said Agent Jimmy Fritts, of the county Metropolitan Narcotics Task Force.

The task force last year investigated 61 cases involving marijuana grows - 30 percent of all drug investigations - and each case is associated with up to 10 grow locations, said Capt. Bruce Wuest.

California guidelines state that a patient can have up to six mature or 12 immature plants and a half pound of processed cannabis, but doctors may recommend more, and local government can enact their own standards.

But in some cases, Fritts said, doctors prescribe outrageous amounts that don't appear to be for personal use.

Turner said he isn't aware of any doctor in the county who issues such medical marijuana recommendations, but growers usually go to doctors in the Bay Area or around Sacramento.

Officials say the issue needs to be addressed at the state level so there are clearer guidelines in the industry.

Meanwhile, local law enforcement is having to make judgment calls on the types of cases it pursues.

They're not going after everyone.

"We're basically getting the ones that are way out of control," Turner said, adding that many times the operations tend to break other rules, including utility theft and unlawful possession of weapons.

For instance, one individual whose name is not disclosed because he is still under investigation for cultivating in an outdoor farm, had a physician's letter that recommended 99 plants and 16 pounds of processed cannabis.

Agents discovered more than 500 plants the size of Christmas trees, as well as illegal weapons. Even if the grower hadn't gone over the threshold, the recommendation amount seemed beyond a person's needs, agents said.

"They'll tell us they're going to use it. That they're going to eat them," Fritts said.

"We have to sit there and argue," said James Boles, another agent with the narcotics unit.

The general public has a perception that marijuana in general - not medical marijuana - is legal, Wuest said. "When in fact there's nothing legal about what they're doing even under state law," he said.

Others think they can beat the system, Turner said.

More individuals - and not always your typical drug dealer with a rap sheet - are jumping into the business even as federal laws continue to conflict with states that have legalized marijuana.

Local businessman Matthew Davies is currently facing 10 years in prison on a federal indictment for cultivating marijuana.

He maintains he was running a nonprofit medical marijuana co-op legitimately and said he is being unfairly targeted by federal authorities even as President Barack Obama has stated he has "bigger fish to fry." Obama was referring to the prosecution of recreational marijuana users in Washington and Colorado, where voters recently legalized recreational marijuana.

"In Matt's case, this is an example of someone doing things right, legally, without tax evasion and without hidden grows," said Steven Ragland, Davies' attorney. "He should not be held up as an example of a person to prosecute."

Ragland said Davies, also a real estate businessman and part-owner of Le Bistro Restaurant in Stockton, consulted with attorneys and tax professionals before establishing dispensaries and grow operations.

Davies, who has a master's degree in business administration, is a family man and has provided tax revenue and more than 100 jobs to the communities where he does business, Ragland said.

And he drew a salary of only $50,000 from the marijuana organizations, Ragland said.

But U.S. Attorney Benjamin Wagner said Davies is being prosecuted because he was a major player in a "very significant commercial operation," according to a letter he wrote to Ragland.

Federal prosecutors say Davies was involved in growing an excess of 2,000 plants, as well as operating at least seven dispensaries that together generated about $3 million.

On Friday, a 62-year-old Stockton woman pleaded guilty in connection to the case. Lynn Farrell Smith, one of Davies' partners, in a plea deal agreed to charges of conspiracy to manufacture and distribute marijuana, two counts of manufacturing marijuana and six counts of distributing marijuana from storefronts in Stockton and Sacramento.

The pool of investigations includes a case that shocked local prosecutors.

County probation employee Alfonso Racacho III recently was arrested in connection to a grow operation in Manteca.

Racacho, who worked in the county Juvenile Justice Department, is being charged with marijuana cultivation, possession of marijuana for sale and theft of utilities. He is scheduled for a preliminary hearing in February.

More often than not, shady operations conceal their activities in homes and farmland without proper authorization from the landlords.

Cornfields become a fortress for hidden outdoor cultivation pockets. The farmers often are not aware someone in charge of the harvest has allowed the activity.

Grow houses are outfitted with shelving and irrigation systems that cause property damage.

In Olaguez's case, one of the homeowners is out an estimated $10,000 to $20,000 in damages to two of his rental homes.

Turner said Pacific Gas & Electric loses hundreds of thousands of dollars from energy theft in such cases - costs that are passed on to customers.

Fires from overworked transformers destroy rental homes and neighboring houses. And the operations are magnets for burglars and robbers.

Authorities say the public should be concerned, because resources are being sucked up by these operations, including enforcement dollars.

As a result, cities are passing ordinances to limit the medical marijuana industry. Manteca has forced the operations indoors, Tracy has excluded them by zoning, and Lodi is currently looking into developing an ordinance.